[Twisted-Python] Help with porting .tac-based custom logging to twisted plugin architecture

[exarkun at twistedmatrix.com]

On 21 Oct, 05:59 am, general at vultaire.net wrote:
>I have an app I'm working on, and until this point it's been done
>utilizing a .tac file.  Recent changes in requirements are encouraging 
>a
>change to use the Twisted plugin system instead.  This seems clear for
>the most part, but I'm unsure about the logging.
>
>Specifically, in the .tac version, I'm using this:
>
>    lf = logfile.DailyLogFile("my.log", ".")
>    logname = "testlog"
>    configure_python_logging(lf, logname)
>    application.setComponent(log.ILogObserver,
>                             log.PythonLoggingObserver(logname).emit)
>
>However, in the plugin version, I'm not sure how to proceed since I
>don't have an application object.  I can't seem to find any
>documentation for configuring logging with plugins, either.  Is there a
>way to make this work?

This is a limitation of the implementation of twistd's plugin support. 
tac files can define custom log observers.  Plugins for twistd cannot. 
Ticket #638 was originally for all of the custom logging feature, but it 
was eventually split up and the tac parts moved to a separate ticket, 
#3534, which is now resolved.  #638 is still open, however.  #3538 is 
another related ticket which proposes an alternate solution to the 
problem, allowing tacs and plugins to be used in combination.

Jean-Paul